Planning Considerations; Cluster Configurations; Active/Active - Compaq ProLiant 1600 Administrator's Manual

2-2 Compaq ProLiant Clusters HA/F100 and HA/F200 Administrator Guide

Planning Considerations

Cluster Configurations

To correctly assess capacity, network, and failover needs in your business
environment, it is important to have a good understanding of clustering and the
things that affect the availability of clusters. The items detailed in this section
will help you design your Compaq ProLiant Cluster so that it addresses your
specific availability needs.
Cluster configuration design is addressed in "Cluster Configurations."
A step-by-step approach to creating cluster groups is discussed in
"Cluster Groups."
Recommendations regarding how to reduce or eliminate single points of
failure are contained in the "Reducing Single Points of Failure in the
HA/F100 Configuration" section of this chapter. By definition, a highly
available system is not continuously available and therefore may have
single points of failure.
NOTE: The discussion in this chapter relating to single points of failure applies only to the
Compaq ProLiant Cluster HA/F100. The HA/F200 includes dual redundant loops, which
eliminate certain single points of failure contained in the HA/F100.
Although there are many ways to set up clusters, most configurations fall into
two categories: active/active and active/standby.
Active/Active Configuration
The core definition of an active/active configuration is that each node is
actively processing data when the cluster is in a normal operating state. Both
the first and second nodes are "active." Because both nodes are processing
client requests, an active/active design maximizes the use of all hardware in
both nodes.